Magnetic die



Jan. 24, 1933.

l. P. SIMONSEN ET AL MAGNETIC DIE Filed Aug. 4. 195

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Patented Jan. 24, 1933 PA TENT Fries IRVING PERCY SIMONSEN AND ARCH C. HUSTON, F LOS ANGELES, CALIFORNIA; SAID SIEv'Z-ONSEN ASSEGNGR T0 SAID HUSTON MAGNETIC DIE Application filed August 4,

This invention has reference to dies, typically of the character used for cutting and shaping sheet metal pieces such as bottoms for paper cans and the like, and is concerned particularly with improvements for eifecting the disengagement or removal of the shaped piece from the die after operation on the piece has been completed.

In cutting and shaping pieces from sheet metal stock by use of the present type of die, the stock is placed between a pair of dies which are caused to move relatively toward and then away from each other in a cutting and forming operation.

In common types of sheet metal dies of which we are aware, the shaped piece, after being cut and formed from the stock by the dies and as the latter move apart, is carried by one of the dies by reason of its frictional engagement therewith. The piece is then disengaged from the die and removed prior to the subsequent operation.

it may be stated that this method of causing the shaped piece to become disengaged from the dies has the disadvantage that frictional engagement between the work and the carrying'die cannot alone be relied upon to insure that the work will always be disengaged from the other die. Such factors as wearing of the die parts and variation in the thickness of the sheet metal stock may cause failure of the parts to function in the manner intended, withthe result that operations are interrupted or-slowed down due to the necessity for manual or gravity manipulation.

These ditiiculties are overcome in accordance with the invention by the provision of a magnetized die adapted to retain the shaped piece as the dies move relatively apart, in

combination with a simple mecaanism for automatically disengaging the work from the magnetized die. By thus causing the work to be held by the carrying die by magnetic attraction rather than by frictional engage ment, it is assured that the operation of disengaging the work from the die will take place in the proper manner regardless of wear on the parts or variations in the thickness of the stock, thus obviating the necessity for 1930, Serial No. 473,112.

frequent attention on the vpart of the opi erator, as has commonly been the'case.

For purposes of describing the invention, I have shown it to be embodied in a typical form of combination die for forming metal bottoms for tubular paper cans. lt-

to be understood, however, that in its broader aspects the invention is not to be regardedas limited to the particulartype of die shown herein, since the invention maybe embodi d in numerous forms of dies without departure from its intended spirit and scope.

Reference is had throughout the following detailed description to the accompanying drawing in which Figure 1 is a front elevational view showing a typical form of die press embodying the invention;

F2 2 is an enlarged fragmentary section taken through-the die parts and showing the work to be pressed between the dies; and

Fig. 3 is a view similar to Fig. 2 but showthe dies in work releasing position. The invention contemplates the use of the hereinafter described die parts in any suit--- able form or design of press. However, as a ypical construction, I show a press comprisng a bed 10 and. an upper archedsupporting rame 11 on which is mounted the upper verical movable die and the operating mechafor that die. The lower stationary die ;eneraliy indicated at 12 is supported on bed 10 and comprises an annulardie block 13 having a cutting edge at 14 and having also a bot m counter-bore 15 between which and the upper bore 16 is presented an annular shoulder 1'1 Within the die block 13 is a stationary block 18 having a cylindrically sh ped upper portion annularly spaced from the walls of bores 15 and 16. A vertically movable lifting ring, or pressure pad 19 is placed within the annular space between blocks 13 and 18, the pressure pad being movable between the limits indicated in Figs. 2 and 3, the latter indicating the normal upper position of the lifting ring in which its upward movement is arrested by the engagement of flange 19a with shoulder 17 in the outer the block. In this position the upper end of the pressure pad is substantially even with the top surface of block 13. The lifting ring is limited in downward movement by the lowest position of the upper die.

Any suitable means may be employed for yieldably supporting the pressure pad in its normal position. As typical of such means I show the pressure pad to be supported on vertically movable pins 22 extending through bores in the bed 10 and block 18 and terminating at their lower ends in a cross piece 23. The latter is slidably mounted on a bolt 24 carried in the bed and is yieldably supported by coil springs 25 bearing against awasher or head. 26 on the lower end of the bolt.

The upper magnetized die generally indicated 27, is mounted on a vertically movable carrier or head 28 which is confined for movement in a vertical path by extensions 29 movable between guide pieces 30 secured to the sides of the frame 11. The head 28 is operated in its vertical reciprocating-movement by connection with a shaft 32, 32a journaled in bearings 33 and driven from pulley wheel 34. On the inner ends of the shaftsections32, 32a are crank arm extensions 35 carrying eccentrically positioned intermediate portion 32?) of the shaft which is connected by rods 37 with pins 39 on the head 28. Thus by virtue of the eccentricity of the intermediate shaft section 32?) with relation to the end portions 32, upon rotation of the shaft there is imparted to the head 28 a vertical reciprocating movement.

Depending from the head 28 is a cylindric core 40, the diameter of which may be slightly less than the diameter of the upper cylindrical portion of the inner block 18 0f the lower die. Core 40 is surrounded by a tubular punch lock 41, the lower reduced diameter end portion 41a of which projects somewhat below the lower end of the core and is adapted to register with the upper end of the pressure pad 19, or in other words the annular space between blocks 13 and 18. Placed within the upper interior of the punch 41 and surrounding the core 40 is an electric coil 42 having lead wires 43 leading to a suitable source of current, not shown. The core 4L0 thus provides an electrode magnet, the purpose of which will presently appear. An air gap is provided at 400! between the lower ends of the core 40 and the punch 41 in order to insulate the magnetized core from the punch ilock to give them opposite polarity.

A pair of what may be termed knock-out pins 43, of brass or other suitable non-magnetic material, is inserted within bores extending longitudinally through the head 28 and core d0, the pins 43 being vertically movable relative to the head assembly. The pins are connected at their upper ends by a cross piece n having an integral depending guide lug as working within bore 46 in the upper end of the head. The knock-out pin assembly is yieldably supported by coil springs 47 which normally, that is when the head is in its lower position shown in Fig. 2, support the pins in such position that their lower ends are raised to a point even with or above the lower end of the core. Upon upward movement of the head to the position of Fig. 3, the upper end of the guide lug 45 projecting above the cross piece 44 is brought into engagement with a stationary stop or abutment i8 depending from the upper portion of the frame 11, so as to arrest further upward movement of the knockout pins with the head and thereby cause them to project below the lower end of the core as shown in Fig. 3. The stop as may be suitably curved longitudinally so as to clear the drive shaft.

In operation, the sheet metal stock 50 is placed between the dies with the parts in the positions of Fig. 3. Upon downward movement of the head to the position of Fig. 2, a circular bottom 50a is cut from the sheet metal stock by the shearing action of the upper die in passing into the lower die bore 16. Upon engagement of the stock by the lower end of the upper die, the pressure ring 19 is displaced downwardly to the limiting position of Figure 2, whereupon the cap is bent around the upper end of the block 18 and formed in the manner indicated. As previously mentioned, this particular form of tin part is suitable for application by subsequent operations to tubular paper cans and similar containers. In the usual die mechanism of this character the frictional engagement of the tin part by the upper die is relied upon to raise the shaped cap out of the lower die and to a position such that it may be taken from between the dies. It will be readily apparent, however, that as the die parts become worn and in the event of substantial variation in the thickness of the stock, the upper die may fail to so pick up the shaped part in the manner intended, in which event manual operation or gravity are relied on to displace the cap.

The invention obviates this difiiculty by the provision of a magnetic pick-up for the tin part and of means for automatically releasing the tin part from the die against the magnetic attraction holding it thereto. Thus upon upward movement of the head, the tin part is held within the upper die by the mag netized core and punch until such time as the cap is disengaged by the knock-out pins. At the point of engagement of the knock-out pin assembly with stop 48, the pins L?) are caused to project below the lower end of the core and to disengage the tin part from the upper die, as will be readily understood. It may be mentioned that in practice the dies will be positioned on an incline, that is,the dies will be inclined with respect to the vertical, so that as the shaped cap is disengaged it will immediately fall or slide by gravity to one side from between the dies and to one side of the hole punched in the stock in order that the dies may be caused to operate at a rapid rate without the necessity for manually removing each formed tin part from between them. For purposes of simplicity in illustrating the invention, the dies are not shown to be so inclined since the invention resides in the die parts themselves and the operation will be readily apparent by illustrating the dies in the position shown.

I claim:

1. In a device of the character described, a pair of dies movable relatively together and apart for operating on a paramagnetic work-piece placed therebetween, one of said dies being magnetized so that as the dies move relatively apart the magnetized die initially retains the shaped piece, and means for subsequently automatically disengaging said piece from the magnetized die upon further separating movement of said dies.

2-. In a device of the character described, a lower die, a vertically movable head above said lower die, an upper magnetized die comprising a magnetized core carried on said head and movable toward and away from said lower die in the operation of shaping a paramagnetic work-piece placed therebetween, said magnetized die carrying the shaped piece with it after operation thereon, means providing a stationary abutment, and a relatively vertically movable member carried by said head and extending through said core, said member being adapted to engage said stationary abutment upon upward movement of the head, a predetermined distance and to disengage the shaped piece from said upper magnetized die.

3. In a device of the type described for shaping sheet blanks of paramagnetic material, a first die comprising aforming head surrounded by an annular groove, a second die comprising a central core portion of paramagnetic material juxtaposed to the forming head of said first die, and an outer annular portion also of paramagnetic material surrounding and spaced from said core portion and juxtaposed to said annular groove in the first die, yoke means of paramagnetic material joining said central and annular portions at the end remote from the die face, a magnetizing winding surrounding said central core whereby the working faces of said core and annular portion constitute opposite poles of an electromagnet for powerfully attracting a work-piece of paramagnetic material positioned between the first and second dies, means for moving said dies toward and away from each other, means for positively dislodging a work-piece from said second magnetic die, and means for actuating said dislodging means when said two dies have separated a predetermined distance.

4L. A device as described in claim 3 in which said first and second dies are positioned for relative movement toward and away from each other in a laterally inclined direction, whereby a Work-piece when discharged from said magnetic die falls clear of said first die.

In witness that I claim the foregoing I have hereunto subscribed my name this 29 day of July, 1930.

ARCH C. HUSTON. IRVING PERCY SIMONSEN. 

